Process of decomposing gas mixtures by means of adsorptive solid substances



July 28, 1925.

F. P. KERSCHBAUM PROCESS OF DECOMPOSING GAS MIXTURES BY MEANS OF ADSORPTIVE SOLID SUBSTANCESv Filed June 9. 1924 A( I Imrgnar:

Pmaadiaiy 2s, i925.

[STATES PATENT; orifice. Y

- :kunnen PAUL xmcxnauir, or mmoar-oN-mnm, annum, assIeNon 'io marcan Lunercoaronariomor Naw You, ir. x., a correa-Arion' or New You raocms or n nconrosme cas To l concern: knownwihat I, Fizinnnicn PAUL mr, of ,the Austrian B .eublic, residing at' Frankfort-on-the-Mam, onig'strassa "12, German have invented certamfnew iid useful provements in Processes of Decomposin Gas Mixtures by -Means of Adsorptive So id Substances, of

' which the following is a specification.

This invention relates to a process of decomposing gas mixtures by means of adsorptive 'solid substances. y e -A number of technical as mixtures have become known, from whic 'certain economically valuable or vapour-constituents are obtainable yA means of adsorptively active solidl substances in an essentially simple n i'anner, by merel passing the gas mixtures over or throug t e granular solid adsor tive agent. In practice however it may uently happen .that the separation of the components of the gas mixture by mbans of the adsorptive substances cannotbe eected so simply, because when passing the gas current over or thro the granular adsorptive agent, not only a sorptive charging'of the latter, but also secondary processes take place which lead to the separation upon the adsorptive agent of sohd or liquid products which coat t e surface of t'he adsorptive agent and co uently destroy the action of the latter in t e course of time. Thus for exam le the distillation gases produced in the distillation of fuels contain more or less large amounts of gaseous light oils according to the fuel employed and the nature of the distillation rocess, which are obtainable in a most simp e manner in princi le, by adsorption upon active carbon. owever, in practice such recoverypf the light oil vapour contents of distillation gases by means of active carbon cannot be leiected long, because the distillation gas,"

besides containing in the form of mistsubstances `such as tar, contains also other f gaseous substances such as for example, sulphuretted hydro volatileorganic oxi.- dizable substances, esides oxygen, and also polymerizable gaseous 'compounds which simultaneously with the adsorptive charging of the active carbon with vaporized hght oil constituents, undergo a chemical transxixruansnx mies or ansmivn senin sunsnicna e appunti@ med im 9, im. sermro. 71am.A A

formation upon 1 the surface of'the active carbon, .leadin Tto -'the formation of solidA or liquid pro ucts which coat the surface and sometimes also' of'liquid water upon the surface of 'the carbon, the effective sur-` face of which is thereby decreased. 'A oontent in certainpol erizable gases or vapours leads to a resinification on the surface of the carbon, which also has adetrimental action upon the adsorptive efficiency of the carbon. y

Ex eri'ments have now revealed theunexpecte fact that it is possible to carry out the adsorptive separation of gas mixtures of the kind above specified, i. e., for example the separation of light oil vapours from gas mixtures containing sulphuretted hydrogen and oxygen, by means of a predetermined amount 'of active carbon permanently and unhindered by detrimental secondary reactions,- if one of the arrangements of the kind hereinafter set forth or a combination thereof `is selected.

1. Ifthe gas mixture, that is for examplev the distillation gas containing light oil and sulphuretted hydrogen and oxygen is suii'- ciently cooled prior to 'its entry into the mass of active carbon which is arranged as a granular ltering layer, it has been found that the active carbon retains the light oil content of the gas mixture quantitatively whilst allowing `the other constituents ofthe as, primarily the sulphuretted hydrogen an oxygen to pass therethrough 55 lof the active carbon and may lrender. the

V- cess is led away behind the 25 able positive heat of adsorption, can in this case no longer rise suiciently high for a reactive transformation yfor example of the sulphuretted hydrogen with the oxygen to take place at the surface of the carbon, to any appreciable extent. On the contrary, the adsorptive eciency is even favoured by the cooling.

2. The as mixture to be se arated, i. e., for examp e the aforesaid distlllation gas is admitted to the solid adsorptive agent which is arranged as an ordinary filtering layer without any preliminary cooling, that is, at ordinary working temperature. According to the invention however the admission of the gas mixture to the active carbon is not effected directly, but as an addition to a gas circuit formed by a suitable gas circulating device in conjunction with the adsorptive filter, and filled originally with any desired gas mixture. If the gas mixture to be separated is supplied to the circuit before the filter (in the direction of flow and the eX- lter, the gas mixture to be treated is caused to pass through the active filter at a considerably increased speed. It will then be found that a sharp separation of the adsorbable gas constitutents occurs without any reactive transformation taking place on the surface of the solid adsorptive agent. The increase in speed apparently causes the zone of adsorptive charging which experience has shown to be very small at the usual slow gas speeds in consequence of the low speed of the gas, and the high speed of adsorption, to be extended considerably in the direction of the flow of the gases, so that the heat of adsorption instead of being concentrated in a thin layer, can be distributed throughout any desired adjustable volume of carbon thereby preventing the occurrence of high temperatures in the zone of adsorptive charging, and thus the occurrence of detrimental secondary reactions which requires a higher temperature than the ordinary working temperature at the surface of the adsorptive substance.

If a number of such gas circuits are connected together in series in which case incidentally, their circuits produced by driving devices may preferably be coupled mechanically together, an arrangement is obtained which, as regards the height of the attainable adsorptive char e of the adsorptive medium does not di er from an ar-V rangement without any gas circuit; the above mentioned adsorptive zone is merely increased in area in accordance with the speed of the gas; the required amount of solid adsorbents is larger and obviously also the total adsorptive capacity of the predetermined amount of adsorbent is correspondingly greater.

A preferable arrangement of filter layers of granular adsorptive material fora sstem of. gas circuits arranged in serial or er 1s obtalned by producin in a vertical shaft by means of correspon ing gas inlets and outlets, filtering layers arranged in series in dlrection of flowwhich on movement of the granular adsorption material in the shaft may travel in counter-current to the gas circulation.

Apparently thus in this second specified manner also, it is possible to effect at suitable working temperatures without any preluninary cooling the complete adsorptive charging of the adsorptive agents corresponding to this temperature whilst avoid lng the occurrence of the above mentioned detrimental secondary reactions, which must damage the surface of the adsorptive medium at any rate after prolonged use.

Thus according to the present invention the two above-described processes exploit practically the temperature co-eicients of opposite sign of the adsorptive charge and of the reactive transformation in a particularly effective manner.

It hfas proved especially advantageous to select as adsorptive agents for processes of the above kind an active substance of good heat conductivity, for instance to select a which- Fig. 1 schematically' illustrates an apparatus comprising a cooler for the gas mixture' Fig. 2 schematically illustrates an apparatus comprising a gas circulating device;

Fig. 3 schematically illustrates al1 apparatus in which the granular material mores counter-current to the gas current; an

Fig. 4 schematicall illustrates an apparatus comprising bot a cooler and a gas circulating device.

Referring to Fig. 1, A is the cooler and B the adsorber. The gas mixture enters through pipe 20, passes through the coil 10 in the cooler and then through the granular adsorptive material 11 in the adsorber.

In Fig. 2 the blower A4 forces the gas mixture to be treated entering through plpe 2O together with the diluting non-absorbable gas from pipe 21, through the adsorptive material 11. The diluting gases may be ob- 22 of the tained by connecting pipe 21 vto the exit pipe complete cycle is formed.

Fig. 3 shows a number of cycles connected in series.- In this arrangement the granular adsorptive material passes downwardl t through a vertical shaft divided by partijcludes an adsorber B,.the gas circulating def` vice comprising pipe 21 and pump A* and a cooler A in the gas supply plpe 20.

What I claim is:

1. In processes of decomposing by means' of solid adsorptive kmaterials as mixtures containing a component to be a` sorbed land a .-.component which tends to produce a. coating upon the surface of adsorptive material an lrender the same inactive, the step which consists in contacting such a gas mixture w1th a solid adsorptive material while maintaining the-temperature within ythe adsorptive zone so low t at the deposition of a coating upon the adsorptive material does not take place.

2. In processes of decomposing by means of solid adsorptive materials gas mixtures containing in addition to an adsorbable component also a component which in the presence of the adsorptive material and under .conditions suitable for the adsorption of thev adsorbable material' is capable of chemical transformation resulting in the deposition 'of a coating uplon adsorber as illustrated, so that al downwardly material.

the surface of the adsorptive material, t e ,step which consists in passing such a gas mixture in contact with a solid adsorptive material while maintainingv the temperature of the gas and the adsorptive material in the adsorption zone so low that chemical transformation and the deposition of a coatin upon the adsorptive material does not ta e place.

3. Process as defined in claim 1 in which the gas mixture is diluted with a gas which isenot adsorbed by the adsorptive material before being contacted with the adsorptive 4. Process as defined in claim 1 in which the gas' mixture is cooled and diluted with a gas which is not adsorbed by the adsorptive material before beingcontacted with the adsorptive material.

5. Process asdened in claim 1 in which a part at least of the gas mixture after bein contacted with adsorptive material is mixe with fresh gas mixture before it is contacted with theadsorptive material.

6: Process as defined in claim 1 in which the gax mixtureis contacted with the adsorptive material in a plurality of succeeding cycles, a portion of the gas after contact with the adsorptive .material in eachecycle 'being mixed with gas mixture entering that cycle, and the remainder of said gas after contact with the adsorptive material in each cycle passing to the next succeeding cycle.

7. Process as defined in claim 1 in which the adsorptive material used is a good conductor of heat-and electricity.

In -testimon whereof in presence o two witnesses. t

' Y 'Y FRIEDRICH PAUL KERSCHQAUII. Witnesses: f

Ronmfr Ermua, Jaim GUIsrr.

I aix .my signature 

